A data policy may specify the data structure for in-memory representation of data, and the read/write scheme for data retrieval. A data policy may specify factors such as whether to prefetch data, reliance on indexes, reliance on memory cache, level of computing power, among other factors.
A data structure is a particular way of storing and organizing data in a computer so that it can be used efficiently. Data structures are generally based on the ability of a computer to fetch and store data at any place in its memory. The type of data structure used (e.g., array, hash table, graph, etc.) is typically selected to maximize efficiency. The type of data structure that will maximize efficiency depends on the application and function that uses the data structure.
An annotation is a special form of syntactic metadata that can be added to the source code of software, particularly within Java source code. Classes, methods, variables, parameters and packages may be annotated. Annotations can influence the run-time behavior of an application.